The bad news for all of you that left WhatsApp for Telegram is that you lost the default encryption. Telegram doesn't encrypt messages by default, like WhatsApp or signal.
But, the good news is that you can enable encryption for specific chats.
Telegram has a so called Secret Chats feature and all messages sent with it are encrypted. So you just have to start a Secret Chat.
Here's how:
✴️ While in a chat, tap that person's profile picture to access his or her profile page;
✴️ Now tap the three dots button on the right to show more options;
✴️ Choose Secret Chat and confirm by taping Start.
Now your all the messages sent through that chat are encrypted and you can even set an auto-disappearing timer so that messages will be deleted after a set time.
Find out more useful tips & tricks on http://ilikeandroid.ro